1. Field of the Invention
The present invention relates to a semiconductor device with a power supply circuit mounted thereon, and a liquid crystal device and electronic equipment using the semiconductor device. Particularly, the present invention relates to a technique for the prevention of malfunctions which may occur in the case of power supply emergencies, such as in the case where a battery is taken out.
2. Description of the Related Art
In a liquid crystal device such as a liquid crystal display, a display operation is implemented when a voltage is applied to liquid crystals which are sealed between substrates in which electrodes are formed. This type of liquid crystal display has been widely used in recent years in various electronic equipment such as personal computers, word processors, cellular phones, electronic pocketbooks, and the like.
Such electronic equipment using a liquid crystal display is designed so that the screen becomes blank instantaneously when the power source is cut off according to a prescribed sequence. The phenomenon of instantaneous lighting occurs when the display is turned off by a procedure other than the above-described sequence, such as the case in which the battery is abruptly drawn out during the display operation, or the electronic equipment is forcedly terninated. Specifically, in this phenomenon the screen image instantaneously disappears when the battery is drawn out during display, following which lighting images such as horizontal lines appear for a while.
The present inventors have conducted extensive studies concerning the instantaneous lighting phenomenon and have achieved the present invention.